• Title, Summary, Keyword: natural draught cooling tower

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Evaluation of Structural Performance of Natural Draught Cooling Tower according to Shell Geometry using Wind Damage Analysis - Part I : One-shell Geometry (풍하중에 의한 손상해석을 이용한 기하형상에 따른 자연 습식 냉각탑의 구조성능 평가 - Part I : One-shell 기하형상)

  • Lee, Sang-Yun;Noh, Sam-Young
    • Journal of the Korean Association for Spatial Structures
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    • v.16 no.3
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    • pp.67-78
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    • 2016
  • Determining of the shape in the process of design for natural draught cooling tower is very important, because the shape of hyperbolic shell is respond sensitively to dynamic behavior of the whole cooling tower against wind load. In engineering practice, the geometric parameters have been determining based on the natural frequency. This study analyses influence of the tower shell geometric parameters on the structural behavior. For three representative models were selected, they were analyzed based on evaluation of damage by means of nonlinear FE-method. As a result, a hyperbolic rotational shell with the small radius overall was the lowest damage index induced by sufficient capacity of the stress redistribution and thus a wind-insensitive structure.

Evaluation of Structural Performance of Natural Draught Cooling Tower According to Shell Geometry Using Wind Damage Analysis - Part II : Two-Shell Geometry (풍하중에 의한 손상해석을 이용한 기하형상에 따른 자연 습식 냉각탑의 구조성능 평가 - Part II : Two-Shell 기하형상)

  • Lee, Sang-Yun;Noh, Sam-Young
    • Journal of the Korean Association for Spatial Structures
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    • v.17 no.1
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    • pp.49-58
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    • 2017
  • The result of the previous work leads to the idea that the inner area of the hyperbolic shell generator should be minimized for the cooling tower with higher first natural frequency. In this study the inner area of the hyperbolic shell generator was graphically established under varying height of the throat and angle of the base lintel. From the graph, several shell geometries were selected and analysed in the aspect of the natural frequency. Three representative towers reinforced differently due to different first natural frequencies were analysed non-linearly and evaluated using a damage indicator based on the change of natural frequencies. The results demonstrated that the damage behaviour of the tower reinforced higher due to a lower first natural frequency was not necessarily advantageous than the others.

Characteristics of wind loading on internal surface and its effect on wind-induced responses of a super-large natural-draught cooling tower

  • Zou, Yun-feng;Fu, Zheng-yi;He, Xu-hui;Jing, Hai-quan;Li, Ling-yao;Niu, Hua-wei;Chen, Zheng-qing
    • Wind and Structures
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    • v.29 no.4
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    • pp.235-246
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    • 2019
  • Wind loading is one of important loadings that should be considered in the design of large hyperbolic natural-draught cooling towers. Both external and internal surfaces of cooling tower are under the action of wind loading for cooling circulating water. In the previous studies, the wind loads on the external surface attracted concernedly attention, while the study on the internal surface was relatively ware. In the present study, the wind pressure on the internal surface of a 220 m high cooling tower is measured through wind tunnel testing, and the effect of ventilation rate of the packing layer on internal pressure is a major concern. The characteristics of internal wind pressure distribution and its effect on wind-induced responses calculated by finite element method are investigated. The results indicate that the wind loading on internal surface of the cooling tower behaves remarkable three-dimensional effect, and the pressure coefficient varies along both of height and circumferential directions. The non-uniformity is particularly strong during the construction stage. Analysis results of the effect of internal pressure on wind-induced responses show that the size and distribution characteristics of internal pressure will have some influence on wind-induced response, however, the outer pressure plays a dominant role in the wind-induced response of cooling tower, and the contribution of internal pressure to the response is small.

Modeling wind ribs effects for numerical simulation external pressure load on a cooling tower of KAZERUN power plant-IRAN

  • Goudarzi, Mohammad-Ali;Sabbagh-Yazdi, Saeed-Reza
    • Wind and Structures
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    • v.11 no.6
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    • pp.479-496
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    • 2008
  • In this paper, computer simulation of wind flow around a single cooling tower with louver support at the base in the KAZERUN power station in south part of IRAN is presented as a case study. ANSYS FLOTRAN, an unstructured finite element incompressible flow solver, is used for numerical investigation of wind induced pressure load on a single cooling tower. Since the effects of the wind ribs on external surface of the cooling tower shell which plays important role in formation of turbulent flow field, an innovative relation is introduced for modeling the effects of wind ribs on computation of wind pressure on cooling tower's shell. The introduced relation which follows the concept of equivalent sand roughness for the wall function is used in conjunction with two equations ${\kappa}-{\varepsilon}$ turbulent model. In this work, the effects of variation in the height/spacing ratio of external wind ribs are numerically investigated. Conclusions are made by comparison between computed pressure loads on external surface of cooling tower and the VGB (German guideline for cooling tower design) suggestions.

Evaluation of Shell Geometry of the Natural Draught Cooling Tower using Linear Numerical Analysis (선형 전산해석을 이용한 자연 습식 냉각탑의 기하형상에 대한 평가)

  • Noh, Sam-Young;Lee, Sang-Yun;Heo, Dong-Hyun
    • Journal of the Korean Association for Spatial Structures
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    • v.12 no.3
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    • pp.97-104
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    • 2012
  • In the design procedure of the cooling tower the form-finding of the shell is the most important process, because the shape of the shell determines the sensitivity of dynamic behaviour of the whole tower against wind excitation. In engineering practice, geometric parameters of the shell are generally determined based on natural frequency analysis. 32 cooling tower shell geometries were selected through variation of the geometric parameters of an existing cooling tower shell. They were evaluated based on the first natural frequency. From the result three representative cooling towers are selected for the analysis of the structural behaviour by means of linear FE-method. As a result, a hyperbolic rotational shell with the small radius overall will yield the shell geometry with a higher first natural frequency and thus a wind-insensitive structure.